The 43-year-old Australian supermodel and her billionaire Snapchat founder husband have shared a video online to assure Californians who might get a letter in the mail advising them that their bills have been erased that the notices are "real" after they teamed up with charity Undue Medical Debt to relieve more than $US550 million ($A798 million) of costs.
Spiegel, 35, said in the Instagram video: "Hey everybody, Spiegel and Miranda here. And today we are so excited because we're announcing a partnership with Undue Medical Debt to relieve over half a billion dollars of unpaid medical debt for more than 250,000 Californians."
Kerr went on to reassure people that their letters were genuine and explained why the couple decided to get involved.
"If you happen to receive a letter in the mail letting you know that your medical debt has been forgiven, we want you to know it's real," she said.
"When someone you love is sick, all you want to do is focus on helping them get better. That's why we wanted to support this effort and help relieve medical debt, so families can focus on caring for their loved ones and really supporting their healing."
The couple explained people had no need to apply to kick-start the process, but beneficiaries would just receive correspondence stating their debt had been "forgiven".
The Kora Organics founder said she and Spiegel were keen to shine a light on the "incredible work" that Undue Medical Debt had been doing since the non-profit was founded in 2014.
According to Undue Medical Debt, Spiegel and Kerr - who have sons Hart, eight, Myles, six, and two-year-old Pierre together, while she also has Flynn, 15, with ex-husband Orlando Bloom - made their undisclosed donation earlier in 2026.